Eagle layout area as library component

Hello,

I’m designing different boards on which i’m always using the same layout for a particular RF part.

I’m wondering how I could integrate part of a layout (2cm square to fix the idea) in an eagle library? I know how to do that for SOIC, etc. components but don’t know how to handle this for a symbol (just like in Cadence, ADS, etc…).

Anybody knows?

Thanks

JPC